Refrigeration system

ABSTRACT

A distributed refrigeration system has a temperature controlled case configured to store and display objects in a facility, a first coolant adapted to cool the objects and circulate through a first cooling system configured to operate with the case, and a second cooling system communicating with the first cooling system to receive a second coolant for removing heat from the first coolant. A method of providing a distributed refrigeration system for delivery to a facility includes providing a temperature-controlled case to store and display objects within a facility, assembling a self-contained first cooling system with the case to circulate a first coolant to cool the objects, and providing a second cooling system communicating with the first cooling system, the second cooling system having a supply connection and a return connection to circulate a second coolant to remove heat from the first coolant.

FIELD OF THE INVENTION

[0001] The present invention relates to a refrigeration system. Thepresent invention relates more particularly to a distributedrefrigeration system.

BACKGROUND

[0002] It is generally known to provide refrigeration systems forcommercial or institutional food sales or food service facilities suchas supermarkets, grocery stores, cafeterias, etc. These refrigerationsystems operate with refrigeration or cooling devices such astemperature controlled cases (individually or in groups) that useair-cooled or water-cooled condensers supplied by a rack of compressors.For example, modern supermarket applications typically have manyindividual or grouped refrigeration devices located throughout theshopping or display area of the supermarket. Each refrigeration deviceis provided with a cooling interface such as an evaporator or coolingcoil that receives refrigerant from the refrigeration system in a closedloop configuration where the refrigerant is expanded to a low pressureand temperature state for circulation through the cooling interface tocool the space and objects within the refrigeration device. In suchapplications, one or more condensers are typically located eitheroutside, on the roof, or in a machine room or back room adjacent to theshopping or display area where the refrigeration devices are located andare used to cool the refrigerant that is distributed to all or a groupof these refrigeration devices.

[0003] In such known refrigeration systems, extensive networks ofrefrigerant piping are often required to interconnect the remotelylocated condensers to the cooling interfaces of the variousrefrigeration devices. These networks of refrigerant piping are oftenexpensive to construct and maintain and are usually coordinated with theconstruction of the facility since the piping is often insulated andconcealed by routing through the floors, ceilings, or walls of thefacility to avoid exposure within the shopping area of the facility.Such known systems require numerous joints and other connections thatare typically field run, installed and tested, and are subject topotential leakage concerns. Such extensive networks of refrigerantpiping also require large quantities of refrigerant that must be chargedafter piping installation in order to properly operate in a closed loopmanner over the extended distances of the network. Generally, the longerthe piping network, the more refrigerant required and the greater thepotential for leakage which creates adverse environmental concernswithin the facilities. The concealed nature of the networks providesfurther difficulty in maintaining the systems due to the difficulty oflocating, accessing and repairing piping leaks. Such refrigerantnetworks also complicate replacement and relocation of the refrigerationdevices within the facility due to the substantially permanent routingof the refrigerant piping and its integration within the facility.

[0004] Efforts have previously been made to address these deficiencies.For example, modular refrigeration systems are generally known, such asthose described in U.S. Pat. No. 5,743,102 titled “Strategic ModularSecondary Refrigeration” issued on Apr. 28, 1998. Such modular systemstypically provide a single rack unit having compressors and a condenserhaving a smaller piping network for connection to a group ofrefrigeration devices (for example, five (5) or six (6) located in aparticular zone of the facility). In such modular systems, a secondarycoolant may be circulated through a second, non-refrigerant pipingsystem having a coolant such as water or a propylene glycol mixture totransfer heat from the local condenser to a remotely located chillerunit. Such known modular refrigeration systems also require field runand assembled refrigerant piping along with the corresponding additionalfittings and connections necessary for supplying multiple refrigerationdevices. Further, such conventional and modular systems often requireseparately wiring the various components of the refrigeration deviceupon installation in the facility, such as wiring for compressor power,control devices, lights, electric defrosting heaters, etc. As recognizedin the 5,743,102 patent, it generally has not been considered feasibleto provide self-contained refrigerated devices or merchandisers forstand-alone operation in a supermarket or other setting for reasons,among others, including high cost, low energy efficiency, and anunacceptably high noise volume from the compressors.

[0005] Accordingly, it would be advantageous to provide a distributedrefrigeration system having a stand-alone refrigeration device with aself-contained refrigeration system that is suitably efficient forcommercial viability. It would be further advantageous to provide adistributed refrigeration system having a sufficiently low noise levelfor use in supermarkets or other consumer-oriented facilities. It wouldalso be advantageous to provide a distributed refrigeration system thatreduces the amount of refrigerant and refrigerant piping within afacility to reduce environmental hazards and to reduce installationcosts, complexity, maintenance and repair time. It would also beadvantageous to provide a distributed refrigeration system having arefrigerant piping system limited to a particular refrigeration deviceand capable of having all refrigerant piping installation andconnections made and pre-charged in a factory setting to minimizeinstallation time and complexity, and to improve flexibility in retrofitapplications. It would be further advantageous to provide a distributedrefrigeration system having a central electrical unit in which allelectrical functions of the distributed refrigeration unit are pre-wiredat the factory and require only a single electrical power hook up wheninstalled at a facility.

[0006] Accordingly, it would be advantageous to provide a distributedrefrigeration system having any one or more of these or otheradvantageous features.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a schematic diagram of a conventional refrigerationsystem.

[0008]FIG. 2 is a schematic diagram of a distributed refrigerationsystem according to a preferred embodiment.

[0009]FIG. 3A is a perspective view of a refrigeration device for adistributed refrigeration system according to a preferred embodiment.

[0010]FIG. 3B is a side view of a refrigeration device for a distributedrefrigeration system according to a preferred embodiment.

[0011]FIG. 4 is a perspective view of a portion of a refrigerationdevice for a distributed refrigeration system according to a preferredembodiment.

[0012]FIG. 5 is a schematic view of an electrical and control system fora distributed refrigeration system.

SUMMARY

[0013] The present invention relates to a distributed refrigerationsystem and includes a temperature-controlled case configured to storeand display objects in a facility, a first coolant adapted to cool theobjects and circulate through a first cooling system configured tooperate with the temperature controlled case, and a second coolingsystem in thermal communication with the first cooling system, where thesecond cooling system is adapted to receive a second coolant forremoving heat from the first coolant.

[0014] The present invention also relates to a method of providing adistributed refrigeration system for delivery to a facility and includesproviding a temperature controlled case adapted to store and displayobjects within a facility, assembling a self-contained first coolingsystem with the temperature controlled case, the first cooling systemadapted to circulate a first coolant to cool the objects, and providinga second cooling system in thermal communication with the first coolingsystem, where the second cooling system has a supply connection and areturn connection to circulate a second coolant to remove heat from thefirst coolant.

[0015] The present invention further relates to a stand-alonetemperature controlled case for a supermarket and includes an enclosurefor storing and displaying objects, a self-contained first coolingsystem having a first coolant, where the first cooling system is coupledto the enclosure and adapted for exclusive use with the enclosure, and asecond cooling system coupled in thermal communication to the firstcooling system and adapted to receive a second coolant from a secondcoolant supply source for removing heat from the first coolant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Referring to FIG. 1, a conventional supermarket refrigerationsystem is shown. As previously discussed, it is conventional practice toplace the compressors 10 and the condenser 12 in a location remote fromthe refrigeration or cooling devices 16. In this conventionalarrangement, the compressors 10 are configured in a parallel banklocated in an equipment room or on the roof or other remote area of thefacility separate from the shopping or display area. The compressorssupply a relatively large condenser 12, which may be air or watercooled. The condenser 12 supplies liquid refrigerant to a receiver 14,which provides a condensed refrigerant reservoir for supplying liquidrefrigerant to the individual refrigeration devices located throughout ashopping or display area within the facility through a refrigerantpiping supply network 20. The refrigerant is expanded in an expansiondevice (not shown) and directed through an evaporator 18 in each of therefrigeration devices 16, where the refrigerant vaporizes as it receivesheat from the space and any objects within the refrigeration device. Thecompressors extract the refrigerant vapor by suction through arefrigerant return piping network 22, and compress the refrigerant backto a liquid state where it is then cooled in condenser 12, whereupon thecycle continues. The refrigerant supply and return piping networks 20,22 are field-run and often routed at least partially through concealedareas of the facility such as floors, walls, ceilings, etc. and havenumerous joints, couplings, fittings and other connections (not shown).

[0017] Referring to FIG. 2, a distributed refrigeration system is shownaccording to a preferred embodiment. Distributed refrigeration system 30may be provided for a single cooling device 32 or may include multiplecooling devices or temperature controlled cases (shown schematically asa low temperature cooling device 34 such as a freezer unit and a mediumtemperature cooling device 36 such a refrigeration unit) located in ashopping or display area 52 of a facility 50 (e.g. supermarket, grocerystore, hotel, restaurant, cafeteria, etc.). In a particularly preferredembodiment, each cooling device includes an enclosure for storing ordisplaying objects in a spaced that is cooled by a direct expansionrefrigeration system having an expansion device 38, a cooling interface40 (e.g. heat exchanger, evaporator, platform with coolant flowpassages, etc.) a compressor 42, and a condenser 44. The refrigerationsystem is provided as a self-contained unit for exclusive use with aparticular cooling device 32, where cooling interface 40 and expansiondevice 38 are provided within cooling device 32 and compressor 42 andcondenser 44 are mounted on or externally to cooling device 32 (shownschematically, for example, as mounted on a top portion of the coolingdevice). The condenser of cooling device 32 is cooled by a secondarycoolant loop 60 using a liquid coolant, such as mixture of water andinhibited propylene glycol. The secondary coolant loop 60 communicateswith a remotely located cooling device, shown schematically as a chiller62, located away from the cooling devices in a remote area 54 (e.g.equipment room, machine room, roof top, etc.). An electrical system, asshown in FIG. 5, is provided to operate and control the variouselectrical components of the distributed refrigeration system andincludes, among others, a controller, solenoid valves, temperaturesensors, switches, compressor motor and control relays and contactors,cabinet lighting within the cooled space of the cooling device, timers,fan motors and control switches, anti-sweat heaters and electric defrostheating elements. In an alternative embodiment, the compressor andcondenser may be mounted in a lower portion of the cooling device, suchas on a slide-out unit for ease of access and maintenance.

[0018] Referring to FIGS. 2, 3A and 3B, the refrigeration system 30 isprovided as a self-contained unit for exclusive use with each coolingdevice. The expansion device 38 and cooling interface 40 may be locatedin any advantageous location within cooling device 32 for communicationwith the space and objects or products (not shown) to be cooled and thecompressor 42 and condenser 44 are provided in a location that does notinterfere with the space or cooling functions of cooling device 32. In aparticularly preferred embodiment, the expansion device 38 and coolinginterface 40 are located in a lower portion of cooling device 32 andcompressor 42 and condenser 44 are located on a top panel 46 of coolingdevice 32. Fans (not shown) may be provided near cooling interface 40 todistribute cooled air from cooling interface 40 within cooling device32. The expansion device 38, cooling interface 40, compressor 42 andcondenser 44 are interconnected in a closed loop configuration by alocal refrigerant piping system 48 to form a primary cooling loop. In aparticularly preferred embodiment, the expansion device 38, coolinginterface 40, compressor 42 and condenser 44 and piping system 48 arepre-assembled and installed on cooling device 32 in a factory settingfor shipment as a stand-alone unit to facility 50. In an alternativeembodiment, the cooling system components and piping may be customconfigured and installed at the facility to suit customer preferences.

[0019] The refrigerant piping system contained locally at therefrigeration system minimizes the amount of refrigerant piping andcorresponding refrigerant required to operate the cooling device 32, andminimizes the number of joints or connections in piping system 48.Further, the ability to pre-assemble, pre-test and pre-charge therelatively smaller piping system 48 and components in a factory settingtends to improve the quality and integrity of the joints to minimizefuture potential refrigerant leakage. The location of the refrigerantpiping solely at cooling device 32 also helps to improve the ability tolocate any leakage that may develop within piping system 48 and theaccessibility of the piping improves the ability to repair such localleakage quickly and cost-effectively. In conventional back-room ormodular refrigeration piping networks the amount of refrigerantnecessary to charge and operate the systems is substantially greaterthan the amount of refrigerant required by the distributed refrigerationsystem. Accordingly, substantial leakage in conventional systems mayoccur before being detected, whereas the smaller amount of refrigerantused by the distributed refrigeration system results in both a smallerquantity of refrigerant available for loss by leakage and the mayincrease the likelihood that leakage would be more readily detectabledue to its more rapid impact on the performance of cooling device 32,thereby reducing the effects of any leakage associated with thedistributed refrigeration system.

[0020] Referring further to FIG. 2, the compressors 42 at both the lowtemperature cooling device 34 and the medium temperature cooling device36 are each sized correspondingly smaller than compressors used withconventional back-rom or modular systems due to the reduced coolingdemand dictated by the standalone nature of the distributedrefrigeration system. Such smaller compressor sizes may operate at lowerefficiencies than the larger compressors of the more conventionalsystems. However, the smaller compressors 42 of the distributedrefrigeration system are capable of operating with a lower refrigerantcondensing temperature than the refrigerant condensing temperatures ofthe conventional systems. In a particularly preferred embodiment, therefrigerant condensing temperature at condenser 44 is in the range ofapproximately fifty (50) degrees F. to sixty (60) degrees F. (however,other suitable temperature ranges may be used in alternativeembodiments). This lower condensing temperature, relative toconventional systems, provides for the use of relatively warmersecondary coolant temperatures at the condenser than are typicallyconsidered feasible for conventional low temperature refrigerationdevices. In a particularly preferred embodiment, the lower refrigerantcondensing temperature associated with the smaller compressor size ofthe distributed refrigeration system corresponds to a secondary coolanttemperature (supplied by another cooling device, such as chiller 62) atthe condenser 44 in the range of approximately twenty (20) degrees F. tofifty (50) degrees F. (however, other suitable temperature ranges may beused in alternative embodiments). This temperature requirement is withinthe operational range of conventional water-glycol solutions forapplications below thirty (30) degrees F. and conventional water coolantfor applications above thirty (30) degrees F. to provide an alternativeto the use of chemicals such as potassium acetate or potassium formatethat are often required in conventional systems having lower coolanttemperature design requirements. The chiller may be an existing chilleralready existing at the facility for use with medium temperature units,or alternatively, may be a custom-sized chiller designed for use withmultiple distributed refrigeration systems intended for use at thefacility.

[0021] In a particularly preferred embodiment, condenser 44 is a shelland coil type condenser that reduces the required amount of refrigerantcharge and the amount of refrigerant flashing, and also preferablyavoids the need for a receiver. Since refrigerant contained in thereceiver of a conventional system tends to gain heat from thesurrounding ambient environment, the additional heat tends to reduce theefficiency of conventional systems. Accordingly, in a particularlypreferred embodiment, the absence of a receiver from the distributedrefrigeration system tends to improve the comparative efficiency of thedistributed refrigeration system. In addition, the lower condensingtemperature of the distributed refrigeration system provides efficiencygains over the conventional systems having higher condensingtemperatures. These collective efficiency gains help to offsetefficiency losses that may result from the use of a relatively smallercompressor 42 in the distributed refrigeration system.

[0022] Referring further to FIG. 2, the secondary coolant system 60 forthe distributed refrigeration system is shown according to a preferredembodiment. Secondary cooling system 60 includes chiller 62, which isshown located away from the shopping or display area 52, such as in aremote area 54, such as an equipment room, machine room, roof toplocation or other convenient location. The chiller 62 provides a sourceof chilled coolant to remove the heat load from condenser 44 at coolingdevice 32. The secondary cooling loop 60 has a supply side 64 and areturn side 66. The supply and return side may have a single branchdirecting secondary coolant to and from a single cooling device, or mayhave multiple parallel branches for directing secondary coolant tomultiple cooling devices (shown schematically for example as twobranches and refrigeration devices in FIG. 2). The branch lines may berouted to the distributed refrigeration system in any convenient mannerand connected to corresponding inlet location 45 and outlet location 47(shown schematically on FIG. 4) to condenser 44. In a particularlypreferred embodiment, flexible hoses are used to connect the secondarycoolant supply and return lines to the inlet and outlet of condenser 44.Accordingly, the distributed refrigeration system provides aself-contained direct expansion refrigeration system in a stand-alonecooling device that may be located at any convenient location within afacility and requires only the routing of a secondary coolant supply andreturn line to the condenser and connection of electrical power. In analternative embodiment, conventional piping (e.g. copper, PVC, etc.) maybe used in place of the flexible hoses to connect the secondary coolantsupply and return lines to the inlet and outlet of condenser.

[0023] Referring to FIG. 4, the condenser and compressor assembly forthe distributed refrigeration system is shown according to a preferredembodiment. In a particularly preferred embodiment, compressor 42 is asemi-hermetic type compressor such as those commercially available fromCopeland Corporation of Sidney, Ohio. The compressor 42 provides asuction source for removing the refrigerant from cooling interface 40.The compressor 42 includes a high pressure switch 86 and a low pressureswitch 88 (shown schematically in FIG. 5) that operate to stopcompressor 42 when the refrigerant pressure is above a predetermined setpoint indicative of an overload condition, and when the refrigerantpressure is below another predetermined set point indicative of a vacuumcondition. The condenser 44 is preferably a shell and coil typecondenser such as those commercially available from the StandardRefrigeration Company of Melrose Park, Ill. The condenser 44 cools thecompressed refrigerant to a temperature within the range ofapproximately forty-five (45) to fifty (50) degrees F. A regulatingvalve 68 senses the pressure of the refrigerant in the compressor andregulates the secondary coolant flow through condenser 44 according tocompressor demand to maintain the condensed refrigerant within thedesired temperature range. In a particularly preferred embodiment, valve68 is a pressure actuated coolant regulating valve, model V46AC-1 of atype commercially available from Penn/Johnson Controls. A compressorrefrigerant suction valve 84 (such as a manual shut-off valve) isprovided for use in activities such as charging the refrigerant pipingsystem 48. In an alternative embodiment, a balancing valve may be usedto control the coolant flow. In other alternative embodiments, othercomponents or component types such as a scroll-type compressor, or othercondensed refrigerant temperature ranges may be used having suitablecharacteristics for operating as a stand-alone distributed refrigerationsystem.

[0024] Referring to FIG. 5, the electrical and control system componentsof the distributed refrigeration system are shown according to apreferred embodiment. Electrical and control system 70 includescompressor motor controls, relays, switches, contactors, transformers,defrost devices (e.g. electric heating elements, etc.), lights,compressor motor wiring, solenoid valves, sensors, etc. In aparticularly preferred embodiment, the electrical and control systemcomponents are pre-wired in a central electrical and control unitconfigured for a single electrical power supply connection duringinstallation at the facility. The electrical system may be configured toreceive any conventional power supply at a facility such as 208 volt,three (3) phase electrical power. In an alternative embodiment, theelectrical and control components may be individually connected or wiredduring installation at the facility to suit customer preference. Theelectrical and control system 70 includes an electrical system 72 havinga central electrical unit 74 that receives a source of electrical powerfrom a conventional electrical power source at facility 50. Centralelectrical unit 74 includes the necessary conventional distribution andswitching apparatus, such as transformers, breakers, contactors,switches, relays, overload protectors, etc. of a standard andcommercially available type for operating the motors associated withcompressor 44 and the fan 76, the defrosting elements 78, cooling devicecase lights 80, the anti-sweat heaters 82 and the compressor high andlow temperature switches 86 and 88. Anti-sweat heaters 82 may beprovided on any surface of the low temperature cooling device 34 ormedium temperature cooling device 36 that may be subject tocondensation, including, but not limited to, doors, windows, walls,panels, air-flow ducts, housings, etc. In an alternative embodiment, thecompressor motor may be supplied by a separate power supply and may alsobe provided with a separate compressor control module including devicessuch as contactors, etc. for operation of the compressor motor. Thecompressor control module may be separately mounted or may be includedas a component within the central electrical unit.

[0025] Referring further to FIG. 5, the electrical and control system 70also includes a control system 100 for controlling the operation ofcooling device 32. Control system 100 has a control module 102 thatreceives electrical power from central electrical unit 74. In aparticularly preferred embodiment, control module 102 includes amicroprocessor having software that may be custom developed in-house ormay be commercially developed according to specifications by acommercial supplier such as Danfoss Inc. of Baltimore, Md. A variety ofsensors may be provided with the distributed refrigeration systemincluding, among others, a cooling interface inlet air temperaturesensor 110, a cooling interface outlet air temperature sensor 112, acooling interface surface temperature sensor 114, cooling interfacerefrigerant pressure sensor 116, a simulated product temperature sensor118, and a cooling device air temperature sensor 120. Sensors 110, 112,114, 118 and 120 may be thermocouples, thermistors or resistancetemperature devices (RTDs) and suited for use with control system 100.The simulated product temperature sensor 118 is provided in a materialhaving the typical mass and thermal inertia characteristics of theproducts intended for storage or display in cooling device 32 and may beused during either or both of initial testing operation or commercialoperation to provide an indication of actual product temperature withincooling device 32. In a particularly preferred embodiment, controlmodule 102 receives a signal representative of temperature from one ormore of sensors 110, 112, 114, 118 and 120 and provides an output signalto control operation of compressor 42, fan 76 and defrosting elements78. Control system 100 includes a timer 104 for initiating a defrostmode of operation on a predetermined frequency (e.g. once per day) wherethe electric defrosting heater elements 78 are energized and compressor42 is temporarily stopped. The duration of the defrost mode of operationis terminated by either of a signal representative of defrostedcondition temperature from cooling interface surface temperature sensor114 or on a predetermined elapsed shut-off time from timer 104 whichacts as a backup device to reinitiate the cooling mode of operation(e.g. by shutting off electric defrost heaters 78 and restartingcompressor 42) in the event of failure of sensor 114. In an alternativeembodiment, the control module software may be developed in-house andthe control module may be configured to receive and send other controlsignals to control the operation of the distributed refrigerationsystem. In another alternative embodiment, the defrost mode of operationmay be initiated without the use of a timer and may be based upon asignal representative of refrigerant pressure within the coolinginterface. In a further alternative embodiment, the defrost mode may becontrolled by any of the sensors that provide an indication of thecooling performance of the cooling interface.

[0026] According to any preferred embodiment, the distributedrefrigeration system provides a stand-alone cooling device with aself-contained refrigeration system that is intended to reduceinstallation time, ownership costs and improve retrofitting flexibilityby providing a pre-assembled unit that eliminates the need for arefrigerant piping network external to the cooling device and thecorresponding additional amount of refrigerant necessary in suchconventional systems with refrigerant networks. The distributedrefrigeration system also gains efficiency from avoidance of a receiverand by using lower condensing temperatures compared to conventionalsupermarket refrigeration systems. The distributed refrigeration systemfurther minimizes the potential for future refrigerant leakage byproviding factory installed piping and connections and piping leakagedetection and repair is more readily addressed by the location,limitation and accessibility of the refrigerant piping. The distributedrefrigerant system also provides for multiple cooling devices havingdifferent temperature applications (e.g. low temperature and mediumtemperature devices) to be cooled by a common secondary coolant andchiller loop.

[0027] According to alternative embodiments, the distributedrefrigeration system may include a medium temperature cooling devicesuch as a refrigerator, a cold storage room, etc. of a low temperaturecooling device such as a freezer case, walk-in freezer, etc. In furtheralternative embodiments, the cooling system may be an open storage ordisplay device such as “reach-in” coolers that may have a fan, airflowpassages or other devices for creating an “air curtain” of cooled airthat creates a boundary between warmer ambient air and the cooled spacein which the objects are stored and/or displayed.

[0028] It is important to note that the construction and arrangement ofthe elements of the distributed refrigeration system provided herein areillustrative only. Although only a few exemplary embodiments of thepresent invention have been described in detail in this disclosure,those skilled in the art who review this disclosure will readilyappreciate that many modifications are possible in these embodiments(such as variations in features such as components, coolantcompositions, heat removal sources, defrosting devices, orientation andconfiguration cooling interfaces, location of components and sensors ofthe cooling and control systems; variations in sizes, structures,shapes, dimensions and proportions of the components of the system, useof materials, colors, combinations of shapes, etc.) without materiallydeparting from the novel teachings and advantages of the invention. Forexample, closed or open space refrigeration systems may be used havingeither horizontal or vertical access openings, and cooling interfacesmay be provided in any number, size, orientation and arrangement to suita particular refrigeration system. According to other alternativeembodiments, the distributed refrigeration system may be used with anycooling device using a direct expansion refrigerant or other coolant fortransferring heat from one space to be cooled to another space or sourcedesigned to receive the rejected heat and may include commercial,institutional or industrial refrigeration devices. According to furtheralternative embodiments, the defrosting of the cooling interface may beprovided by warm air circulation, hot gas (i.e. refrigerant)circulation, or circulation of a liquid coolant. Further, it is readilyapparent that variations of the distributed refrigeration system and itscomponents and elements may be provided in a wide variety of types,shapes, sizes and performance characteristics, or provided in locationsexternal or partially external to the refrigeration system. Accordingly,all such modifications are intended to be within the scope of theinventions.

[0029] The order or sequence of any process or method steps may bevaried or re-sequenced according to alternative embodiments. In theclaims, any means-plus-function clause is intended to cover thestructures described herein as performing the recited function and notonly structural equivalents but also equivalent structures. Othersubstitutions, modifications, changes and omissions may be made in thedesign, operating configuration and arrangement of the preferred andother exemplary embodiments without departing from the spirit of theinventions as expressed in the appended claims.

What is claimed is:
 1. A distributed refrigeration system, comprising: atemperature controlled case configured to store and display objects in afacility; a first coolant adapted to cool the objects and circulatethrough a first cooling system configured to operate with thetemperature controlled case; and a second cooling system in thermalcommunication with the first cooling system, the second cooling systemadapted to receive a second coolant for removing heat from the firstcoolant.
 2. The distributed refrigeration of claim 1, wherein thefacility is one of a supermarket, grocery store, convenience store,cafeteria, hotel or restaurant.
 3. The distributed refrigeration systemof claim 1, wherein the first coolant is a vapor expansion refrigerantand the second coolant is one of water and a solution of water andpropylene glycol.
 4. The distributed refrigeration system of claim 1,wherein the first cooling system is a vapor expansion refrigerationsystem configured to operate exclusively with the temperature controlledcase.
 5. The distributed refrigeration system of claim 4, wherein thefirst cooling system is a closed loop system coupled to the temperaturecontrolled case in a stand-alone configuration.
 6. The distributedrefrigeration system of claim 5, wherein the first cooling system ispre-assembled with the temperature controlled case for delivery to thefacility.
 7. The distributed refrigeration system of claim 6, whereinthe first cooling system is pre-charged and pre-tested for delivery tothe facility.
 8. The distributed refrigeration system of claim 1,further comprising a central electrical unit coupled to the temperaturecontrolled case and adapted to receive a single electrical supplyconnection at the facility.
 9. The distributed refrigeration system ofclaim 1, wherein the secondary cooling system further comprises a supplyconnection and a return connection adapted to couple the secondarycooling system to a secondary coolant supply source at the facility. 10.The distributed refrigeration system of claim 9, wherein the supplyconnection and the return connection are flexible hoses.
 11. Thedistributed refrigeration system of claim 3, wherein the first coolingsystem includes a compressor, a condenser, an expansion device and acooling interface.
 12. The distributed refrigeration system of claim 11,wherein the refrigerant has a condensing temperature in the condensergenerally within the range of fifty degrees F. to sixty degrees F. 13.The distributed refrigeration system of claim 12, wherein the secondcoolant has a supply temperature at the condenser generally within therange of twenty degrees F. to fifty degrees F.
 14. A method of providinga distributed refrigeration system for delivery to a facility,comprising: providing a temperature controlled case adapted to store anddisplay objects within a facility; assembling a self-contained firstcooling system with the temperature controlled case, the first coolingsystem adapted to circulate a first coolant to cool the objects; andproviding a second cooling system in thermal communication with thefirst cooling system, the second cooling system having a supplyconnection and a return connection adapted to circulate a second coolantto remove heat from the first coolant.
 15. The method of claim 14,wherein the facility is one of a supermarket, grocery store, conveniencestore, cafeteria, hotel or restaurant.
 16. The method of claim 14,further comprising providing a control system to regulate operation ofthe temperature controlled case in an operating mode and a defrost mode.17. The method of claim 14, further comprising pre-testing the firstcoolant system.
 18. The method of claim 14, wherein the first coolant isa refrigerant and pre-charging the first cooling system with therefrigerant.
 19. The method of claim 14, further comprising providing acentral electrical unit that is pre-wired to the temperature controlledcase and to the first coolant system and adapted to receive anelectrical supply connection at the facility.
 20. The method of claim15, wherein the second coolant is a propylene glycol solution providedby a second coolant supply at the facility.
 21. A stand-alonetemperature controlled case for a supermarket, comprising: an enclosurefor storing and displaying objects; a self-contained first coolingsystem having a first coolant, the first cooling system coupled to theenclosure and adapted for exclusive use with the enclosure; and a secondcooling system coupled in thermal communication to the first coolingsystem and adapted to receive a second coolant from a second coolantsupply source for removing heat from the first coolant.
 22. Thestand-alone temperature controlled case of claim 21, further comprisinga central electrical unit coupled to the enclosure and adapted toreceive a single electrical connection at the supermarket.
 23. Thestand-alone temperature controlled case of claim 21, wherein the firstcooling system includes a compressor and a condenser.
 24. Thestand-alone temperature controlled case of claim 23, wherein thecompressor is a semi-hermetic compressor and the condenser is ashell-and-coil type condenser.
 25. The stand-alone temperaturecontrolled case of claim 21, wherein the first cooling system ispre-assembled and pre-tested in a factory.
 26. The stand-alonetemperature controlled case of claim 23, wherein the first coolant is avapor-expansion refrigerant having a condensing temperature in thecondenser generally in the range of fifty degrees F. to sixty degrees F.27. The stand-alone temperature controlled case of claim 21, wherein thesecond coolant is a propylene glycol solution having a supplytemperature at the condenser generally within the range of twentydegrees F. to forty-five degrees F.